Diagnostic Approach to Peripheral Arterial Disease

Initial Diagnostic Testing

The American College of Cardiology recommends a resting Doppler ankle-brachial index (ABI) as the initial diagnostic test for peripheral arterial disease (PAD), with a Class I, Level B recommendation, and may be the only test required to establish diagnosis and institute guideline-directed medical therapy 1, 2, 3
The resting ABI has a sensitivity of 69-79% and specificity of 83-99% compared with imaging studies showing significant arterial stenoses in symptomatic patients 1, 4
The American College of Cardiology suggests that the resting ABI is noninvasive, simple to perform, has minimal risks, and is suitable as both a screening and diagnostic test 1, 4

The American College of Cardiology recommends reporting results using standardized criteria, where an ABI ≤0.90 confirms PAD diagnosis, 0.91-0.99 is borderline and requires clinical context, 1.00-1.40 is normal, and >1.40 suggests arterial calcification 1, 2, 5, 6
An ABI >1.40, which is common in elderly patients with diabetes or chronic kidney disease, may require measurement of toe-brachial index (TBI) instead 1, 4
A TBI ≤0.70 is abnormal and confirms PAD diagnosis 1, 4

The American College of Cardiology recommends segmental pressures with pulse volume recordings (PVR) and/or Doppler waveforms as Class IIa recommendations to localize anatomic segments of disease and confirm concordance with PAD presence and severity 1, 3
The American Heart Association suggests that anatomic imaging studies (duplex ultrasound, CTA, MRA, or catheter angiography) are generally reserved for highly symptomatic patients in whom revascularization is being considered, when symptoms are functionally limiting and response to medical therapy is inadequate, or to assess anatomy and determine revascularization strategy 1, 2, 5

The American College of Cardiology recommends measuring blood pressure in both arms, as an inter-arm difference >15-20 mmHg suggests subclavian stenosis and affects ABI accuracy 2, 3
The American College of Cardiology suggests using the higher of the two ankle pressures (dorsalis pedis or posterior tibial) for diagnostic purposes to minimize overdiagnosis 6